Rheem RGPH-07EAMGR Error Code 1 Blink (2-sec pause): 1 Hour Lockout
What Does Code 1 Blink (2-sec pause) Mean?
On the UTEC 1012-925 Integrated Furnace Control (IFC) in the Rheem RGPH-07EAMGR, the "OK" status LED flashes once and then pauses about two seconds to report a 1-hour lockout. The board reaches this state only after it has tried to light the burners four times without confirming a flame. During each trial it energizes the gas valve for just about 8 seconds; if the flame-sensing circuit does not prove a flame in that window, the trial fails.
Because this is a single-stage furnace with a 115 VAC hot surface igniter, the board relies on the flame sensor rod to confirm ignition on every cycle. The most frequent field cause of repeated failed trials is a flame sensor coated with oxide or carbon buildup — the burners may actually light, but the board cannot "see" the flame, shuts the gas, and counts the trial as a failure. Other causes include a manual gas supply valve that has been turned off, a hot surface igniter that no longer glows, or no gas reaching the valve.
After the fourth failure the board holds the lockout for one hour, runs the blower and induced-draft blower for about 100 seconds to clear the heat exchanger, then retries automatically. Do not confuse this single-blink status-LED lockout with the separate amber flame-sense LED: a slow amber flash (see Marginal Flame Sense Current) warns of a weak-but-real flame signal before a full lockout occurs, while a rapidly blinking amber LED points to flame detected when none should be present.
What You'll Notice
- The status LED repeats a single blink then a 2-second pause, and the furnace makes no heat for up to an hour.
- You may hear the igniter glow and the burners light briefly, then shut off after a few seconds, repeating up to four times.
- Warm air never reaches the registers; the blower and inducer run for about 100 seconds after the last failed try before going quiet.
- The furnace attempts to relight on its own roughly an hour later.
Common Causes
How This Is Diagnosed
The cause is isolated in the order the board tries to light. First confirm the manual gas supply valve is fully open, then inspect the flame sensor rod for buildup, since a dirty sensor is the most common reason the burners light but the board fails to prove flame. If the sensor is clean and gas is present, a technician checks whether the 115 VAC hot surface igniter actually glows and whether gas reaches and leaves the gas valve during each 8-second trial.
How to Fix It: Clean the Flame Sensor and Confirm the Gas Supply Is On
What You'll Need
Steps
- Shut off power and gas before you start Turn off the furnace power switch or the breaker, and shut off the gas supply valve to the furnace. If you smell gas, leave immediately and call your gas company from outside. Give the furnace a few minutes to cool before opening it.
- Confirm the manual gas supply valve is open Before cleaning anything, check that the manual gas shutoff valve feeding the furnace is fully open (handle in line with the pipe). A valve left closed after other work is a common reason the furnace cannot light. Leave it shut off for now while you clean the sensor; you will reopen it at the end.
- Locate and remove the flame sensor Open the burner compartment and find the flame sensor — a single metal rod mounted at the far end of the burners with one wire attached. Remove its retaining screw and gently pull the sensor out, noting how it sits.
- Clean the sensor rod Gently clean the flame sensor rod with a Scotch-Brite pad until the metal is dull-bright. Rheem's guide lists fine steel wool as the cleaning material, but many HVAC technicians prefer a Scotch-Brite pad because it leaves no abrasive residue on the rod. Do not clean or scratch the white porcelain base, and take care not to bend the rod.
- Reinstall and restore power and gas Reseat the sensor and its screw, reconnect the wire, and close the panel. Reopen the gas supply valve fully, then restore power and let the furnace run through its ignition sequence.
When to Call a Professional
Contact a licensed HVAC technician if:
- The furnace keeps entering the 1-hour lockout after the flame sensor is cleaned and the gas supply is confirmed on
- The igniter never glows, or the burners never light during the ignition attempts
- The burners light but the flame is weak, yellow, or lifts off the burner
- You smell gas at any point, or the furnace short-cycles on and off repeatedly
Frequently Asked Questions
Will my Rheem furnace fix itself after the 1-hour lockout?
The board retries automatically once the hour is up, so heat may return on its own if the cause was temporary. But if a dirty flame sensor or another underlying fault remains, it will simply lock out again after the next four failed tries.
Why does the furnace try four times before locking out?
The UTEC control gives the burners four chances to light, energizing the gas valve for about 8 seconds each try. Four failures in a row trigger the one-hour safety lockout so raw gas is not repeatedly introduced.
How often should the flame sensor be cleaned?
Most homes benefit from a cleaning about once a heating season, though dusty or high-humidity environments may need it more often. There is no fixed schedule, and needs vary by region and air quality.
Sources
✓ Verified against manufacturer service manual — March 2026